#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <iostream>
#include <queue>
#include <vector>

using namespace std;

struct ListNode {
    int val;
    ListNode* next;
    ListNode(int x) : val(x), next(NULL) {}
};

class Node {
   public:
    int val;
    Node* next;
    Node* random;

    Node(int _val) {
        val = _val;
        next = NULL;
        random = NULL;
    }
};

struct TreeNode {
    int val;
    TreeNode* left;
    TreeNode* right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
   public:
    char firstUniqChar(string s) {
        int alphabet[26], firstPos;
        memset(alphabet, 0, sizeof(int) * 26);
        for (int i = 0; i < s.size(); i++)  alphabet[s[i] - 'a']++;
        for (firstPos = 0; firstPos < s.size(); firstPos++) {
            if (alphabet[s[firstPos] - 'a'] == 1) return s[firstPos];
        }
        return ' ';
    }
};

int main() {
    cout << "Hello, World!";
    // Solution()
    return 0;
}
